Am I thinking right? I have a MSD distributor with mechanical advance that I'd like to limit. Knowing the total amount of advance built into the distributor, say 16 degrees, and I attach a cheap plastic protractor to the advance unit to get the arc of the unit, then limit the arc to say half of the advance travel (limited by a ground down screw edge) would that be 8 degrees of advance?

"Am I thinking right? I have a MSD distributor with mechanical advance that I'd like to limit. Knowing the total amount of advance built into the distributor, say 16 degrees, and I attach a cheap plastic protractor to the advance unit to get the arc of the unit, then limit the arc to say half of the advance travel (limited by a ground down screw edge) would that be 8 degrees of advance? "
Yes. Most every MSD I messed with had 24 degrees built in from the factory. I'm not saying all are, just the ones I played with.
I'll also say that they(MSD) are extremely proud of their bushings. I mean I'm pretty sure a CNC lathe, or screw machine could spit out a couple thousand in a good day. 2,000 x $25 = $50,000 Not a bad days work.IMO
ssmonty

Am I thinking right? I have a MSD distributor with mechanical advance that I'd like to limit. Knowing the total amount of advance built into the distributor, say 16 degrees, and I attach a cheap plastic protractor to the advance unit to get the arc of the unit, then limit the arc to say half of the advance travel (limited by a ground down screw edge) would that be 8 degrees of advance?

That would theoretically get you in the ballpark.

Make a timing tape if you don't have a dial back timing light. You are going to want to verify any such modifications- going by eye is not something you want to do w/the ignition timing, especially in that the total timing- if excessive- can harm the engine.

Click on image for instructions:

FWIW, besides the MSD bushings (28 degree, 25 degree, 21 degree and 18 degree), there are aftermarket 10 and 14 degree bushings, but damn are they proud of them!

Should have put this in the original post. What I'm trying to do is run as much initial advance as I can without locking it at 36 as I think 36 would be to much in my case with the 91 octane around here.

Flat top pistons, no vacuum advance. Good gas is about 30 miles away. 55 gallon drum and pump time. Or, a case of toluene from Lowes? lol Guess I could set the timing for the 91 octane and advance it at the track with good gas. I drive to the track 85 or 130 mile depending on which one I go to.

Lock the timing- it's a no-brained way of not actually doing the small amount of work required to actually correctly set up the ignition advance. Then you can brag you have the same timing setup as your B&S lawn mower. And w/luck, you'll be able to out run one, too- but I'm not betting on it outlasting one.

There are GOOD reasons for not using max power timing below 3000 rpm or so. Lock the timing at an arbitrary 36 degrees and you'll likely find out why, sooner or later. The risk of detonation is ANY TIME the engine is under a load!!!!!!!!!

Before you make a mistake, take the time to absorbe the info here. If there's anything that's unclear to you, just ask. This is nothing to be scared of- it only takes a bit of a learning curve (npi) and you'll have the best of both worlds.

fb, the ONLY appeal your "one size fits all", no-brained "advice" has, is that it is easy for you to post.

To the OP, I say: It is up to YOU to sort through the BS. It is up to YOU to do your due diligence. I cannot do anything more than supply the info. The rest is up to you and to how much desire you have to do the job right.

More timing does not always (or even mostly) mean max timing (i.e. locked timing) all the time. You are clueless. The engine can- and WILL- detonate w/max power timing if it's under a load- that's the reason for having a curve, otherwise there wouldn't be mechanical advance distributors.

You are trying to turn every engine you post to into a drag-only deal. Too much timing, too much cam, too much CR, too high stall speeds, and top it off w/305 heads on everything. Unless this guy wants a 1 trick pony- like your advice- he needs to do some research. The ONLY thing that might save the OP from grief is it's "only" a 20% street deal. But you give the same advice, regardless if it was 100% street, so still a 1-trick pony.

It's really very simple- an engine that can use a timing curve is better equipped to handle a variety of situations than an engine w/o a curve. It negates any need for an ignition interrupter. It protects against detonation when under a load at low rpm.

The difference is in philosophy. Some start safe and work upwards from there. Some jump in head first w/o caring what the results may be. After all, you will be nowhere to be found if the engine is scattered.

EVERY ENGINE/COMBO/VEHICLE IS DIFFERENT. Blanket advice to always lock the timing is not good advice- it is only EASY advice. And that sort of "advice" only gets any play because there are a few guys who prefer easy over correct.

But what's this I see? "If you want to create a short 8deg timing curve go ahead"?? At least you finally admit that a curve is possible, and you'd be surprised at just how much curve you can get if you actually work towards that end! If you think a curve has no use, then I cannot help your ignorance of the facts.

If you are racing, but you want to limp around on the street. A beginner would find locked timing works well if you have a high stall and track gear. Then you could also go from light to light around town.

From the majority of the builds, I would imagine from the numbers they target, This is what they want. Either that or they have unrealistic goals. It seems people want more than the RPM smallblock. That is a pretty hot 350, my opinion at least.

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